Development of Technology for Recycling Copper Smelting Production Waste

Metallurgist - Extensive research is conducted and a production scheme is proposed, including recovery of copper-containing slag with coke carbon and neutralization of waste copper electrolyte with...     

Thermal expansion of arsenopyrite in helium and air

The mineral arsenopyrite was studied by high-temperature x-ray diffraction in helium and air. The lattice parameters and chemical strain were determined as a function of temperature.     

Low-shrinkage mixtures with quartz-sericite-chlorite shale for ceramic tile

Low-shrinkage mixtures with quartz-sericite-chlorite shale for exterior and interior facing tile are studied. The tile is characterized by a high bending strength and cold resistance. The properties of the tile produced on an industrial scale meet the requirements of the standards.     

Application of Sulfide Copper Ores Oxidizing Roasting Products as Sulfidizing Agent During Melting Nickel Raw Materials To Matte

Metallurgist - X-ray fluorescence analysis, X-ray powder diffraction, electron microprobe analysis, scanning electron microscopy, and thermal analysis are used to evaluate the material composition,...     

Design of Liquid-Ring Vacuum Pump with Adjustable Degree of Internal Compression

Chemical and Petroleum Engineering - Liquid-ring vacuum pumps are used in oil recovery, in processing of plastics, in distillation processes, and other elsewhere. A major drawback of liquid-ring...     

A four-quadrant voltage converter (600 V, 500 A)

A power system based on regulators connected in a pulse-width modulation (PWM) half-bridge circuit with up-to-date power IGBT switches. The system ensures the four-quadrant operation with an out-put voltage of up to 600 V and current of up to 500 A. The control system is based on a digital signal processor and ensures all necessary measurements, interlocks, PWM signal generation, and communication with the computer.     

Electrochemical oxidation of nickel sulfide metallic alloys

The sequence of the electrochemical oxidation of phase components of the converter matte is confirmed and variations in the composition of its surface during the anode oxidation are revealed. It is shown that regularities of this process that are characteristic of its phase components, namely, nickel and its sulfides, are inherent to the converter matte. The oxidation of nickel sulfides in sulfide-metallic alloys starts at lower potentials (1.1–1.2 V) than that of synthesized nickel sulfide (1.2–1.3 V). During the oxidation of the converter matte, metal nickel initially oxidizes and, only as this stage finishes, the oxidation of sulfides accompanied by the isolation of elemental sulfur is developed. Copper impurities weakly affect the oxidation of the converter matte, although the shift of potentials takes place as the Cu/Ni ratio increases.     

Uncertainty of a measured result and confidence error of measurements

An analysis is made of the known information concerning the concepts of error and uncertainty and it is concluded that they are identical.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 14–17, August, 1994.